The present invention generally relates to quick-release fasteners, and more specifically relates to a fastener system for use in quickly and easily attaching or securing one structural body to another, such as for quickly and easily attaching a panel to aircraft structure.
A typical panel fastener system includes a fastener having a head, a shank, and a threaded portion formed on the shank opposite the head. The threaded portion is engageable with a corresponding threaded nut. For example, in the case where the fastener system is used to secure or attach a panel to an aircraft structure, the nut is secured on the aircraft structure where the panel is to be attached. To install the fastener and attach the panel, the fastener is inserted through an aperture in the panel, and then the threaded portion of the shank is engaged with the nut thereby securing the panel in position. Prevailing (locking) torque helps the fastener resist loosening under vibration. Typically, several fasteners are employed to secure a panel in place on an aircraft. This is especially true in cases where the panel is large and/or is load-carrying.
One of the problems with prior art fastener systems is that by providing that the threaded portion of the shank must be threadably re-engaged with the nut each time the fastener is attached or installed, there is a tendency for the prevailing locking torque between the parts to become worn. In other words, the life cycle of prior art fastener systems is often limited by how many cycles it takes for the locking torque between the shank and the nut to become reduced to unacceptably low values.
Additionally, prior art fastener systems provide that the shank must be rotated several times, such as 6-10 times, with respect to the nut in order to fully install the fastener system. This process is generally time consuming and tedious, especially so if the process must be repeated for several fasteners.
Another problem with the prior art fastener systems is that they typically include numerous, loose components, including at least the fastener and a separate nut. Many prior art fastener systems which are not captive fasteners provide that once the fastener has been released to remove one structural body from another, the fastener can readily fall away. For example, in the case of a panel on an aircraft where the panel pivots downward upon the one or more fasteners being disengaged from the aircraft body, the fasteners can readily fall to the floor. This is not only inconvenient, but can result in losing a fastener thereby further increasing the time to effect the re-attachment of the panel.
Yet still another problem with those prior art fastener systems which are not hold-out fasteners is that when, for example, a panel is removed or pivoted generally away from the aircraft body, the fasteners, even if they do remain on the panel, pivot slightly due to gravity and are not generally aligned relative to the nut to allow for the easy re-installation of the fasteners to re-attach the panel. The fact that the fasteners can pivot with respect to, for example a panel, after the fasteners are released may provide that as the panel is re-aligned for re-attachment, the fasteners are not aligned with their respective nuts.